Hidden-density regions: clusters of census tracts whose combined density far exceeds the area average, shown with current and future rapid-transit corridors.
Loading…
Study area
Loading county index…
The study area sets the benchmark for population and land shares. Tract geometry loads per county as you pan and zoom in; regions may span counties.
Region editor
Choose a destination region, then click any tract. Choose Unassigned to remove a tract from its region. Moving a tract between regions is allowed. Delete region turns its tracts into ordinary unassigned tracts and renumbers the rest. Save browser keeps a quick local copy; Export JSON writes a portable region-set file that Import JSON reads back (older v3/v4 exports are accepted too).
Choose a region to edit.
Hover or click a tract to inspect it.
Regions · population · area · density
Highlighted regions combined
Calculating…
Uncheck any region to isolate the others. Click a region tract for details.
Export is rendered on a separate off-screen map, so its framing and resolution are independent of your browser window.
Map exports use a dedicated off-screen Leaflet map at the selected pixel size and geographic bounds. Larger output sizes make Leaflet request more detailed tiles instead of enlarging a screenshot.
Population and land area: 2020 Census (P.L. 94-171 population, TIGER land area) for every California tract. Tract geometry: Census cartographic boundary files (1:500k) statewide, with street-accurate TIGER/Line geometry for the Los Angeles and Bay Area preset counties. Current Metro rail and stations load from public ArcGIS feature services; future corridors are planning-level schematic alignments and are drawn dashed. The shipped region set is never overwritten; edits live in your browser or in exported JSON.